Prosthetic heart valves have been used for replacing damaged or diseased heart valves in patients. Various types of prosthetic heart valves are known, including mechanical heart valves and bioprosthetic heart valves. Bioprosthetic heart valves may include a material, such as tissue or synthetic polymers, carried on a stent. The material typically comprises animal tissue, such as porcine aortic valve material or bovine pericardium.
Different techniques are known for coupling the material to the stent. For example, suturing the valve material to the stent is one common technique. However, such suturing has been found to place stress on the material as the valve opens and closes, thus leading to a shorter useful life for the prosthetic heart valve. In fact, any attachment technique which creates a hole in the tissue near the post tips may concentrate destructive stresses in those areas.
Various types of attachment techniques are shown in, for example, U.S. Pat. No. 4,501,030, issued Feb. 26, 1985, entitled “METHOD OF LEAFLET ATTACHMENT FOR PROSTHETIC HEART VALVES”, U.S. Pat. No. 4,441,216 issued Apr. 10, 1984, entitled “TISSUE HEART VALVE AND STENT”, U.S. Pat. Nos. 5,163,955, 5,423,887 and 5,489,298 to Love and U.S. Pat. No. 4,725,274, to Lane which issued Feb. 16, 1988.
One limitation frequently found in prior art stented valves is that the mechanism which attaches the leaflet to the stent prevents the leaflet from fully opening. This reduces the maximum diameter of the central lumen through the valve and impedes blood flow. Further, the leaflets can experience high stress in the attachment region. Stentless heart valves are also known in the art. However, such valves typically require more then one suture line to implant. Further, because they are not rigid, they may be more difficult to position correctly than stented valves.